Ga–In intermixing, intrinsic doping, and Wigner localization in the emission spectra of self-organized InP/GaInP quantum dots. (31st October 2016)

• Record Type: Journal Article
• Authors: Kapaldo, J; Rouvimov, S; Merz, J L; Oktyabrsky, S; Blundell, S A; Bert, N; Brunkov, P; Kalyuzhnyy, N A; Mintairov, S A; Nekrasov, S; Saly, R; Vlasov, A S; Mintairov, A M
• Is Part Of: Journal of physics. Volume 49:Number 47(2016)
• Publication Date: 2016-10-31
• Subjects: quantum dot -- intermixing -- optical properties -- electronic properties; Physics -- Periodicals; 530
• DOI: 10.1088/0022-3727/49/47/475301
• Languages: English
• ISSNs: 0022-3727

Abstract

Abstract: We present study of structural and optical properties of InP/GaInP quantum (QDs) providing a weak quantum confinement and creating a platform to study Wigner localization (WL) effects using high spatial resolution optical spectroscopy. Self-organized QD structures were grown using metal-organic chemical phase epitaxy by using different substrate misorientations and cap layer deposition temperatures. Using transmission electron microscopy and energy dispersive x-ray spectroscopy, we demonstrated a bimodal height distribution with peaks at ~5 and ~20 nm and a control of both the lateral size distribution, peaked from ~100 to ~160 nm, and the amount of Ga–In intermixing in the QDs (up to 20%). Using photoluminescence (PL) spectroscopy in combination with circular polarization degree and time resolved micro-PL measurements, we demonstrated control of the emission energy, the intrinsic doping, and the emission decay of these In(Ga)P QDs. Using high-spatial-resolution near-field PL spectra and imaging of single dots, we demonstrated WL effects in dots having a population of up to nine electrons and a parabolic confinement down to ħω 0 ~ 1 meV. We performed a self-consistent calculation of exciton transitions using an effective mass, mean field theory with an isotropic elasticity model to describe the effect of Ga–In intermixing on the emission properties of these dots; and we used calculations of shell splitting, using mean field Hartree–Fock approach and calculations of electron density distribution using configuration interaction approach, to described effects of enhancement of WL in non-circular dots with hard-wall potentials.